The present invention relates to a rock drilling tool, comprised of a drill body and a reamer mounted thereon for radial extension and retraction.
In known drilling tools of the above-mentioned type, drawbacks result from screw thread connections, for example between the guiding means and the part which carries the reamer, because there always occur energy losses in threaded joints which transfer impact energy.
Another known tool is shown in applicant's U.S. Pat. No. 5,284,216 wherein the shank and the drill bit constitute an entity on which a guide is arranged. However it has been experienced that the known tool comprises a number of drawbacks; the reamer cannot easily be exchanged, the impact energy cannot be maximally utilized, the position of the grooves cannot be placed optimally, and locking means for threads has poor strength and is troublesome to handle.